Smart Anisotropic Wetting Surfaces with Reversed PH-Responsive Wetting Directions.
writer：Peng Ge, Jianglei Zhang, Yongshun Liu, Shuli Wang, Wendong Liu, Nianzuo Yu, Yuxin Wu, Junhu Zhang
keywords：none
source：期刊
specific source：Adv. Funct. Mater.
Issue time：2018年
Smart pH-responsive surfaces that could autonomously induce unidirectional
wetting of acid and base with reversed directions are fabricated. The smart
surfaces, consisting of chemistry-asymmetric “Janus” silicon cylinder arrays
(Si-CAs), are prepared by precise modification of functional groups on each
cylinder unit. Herein, amino and carboxyl groups are chosen as typical
pH-responsive groups, owing to their protonation/deprotonation effect in
response to pH of the contacted aqueous solution. One side of the Si-CAs
is modified by poly(2-(dimethylamino)ethyl methacrylate), while the other
side is modified by mixed self-assembled monolayers of 1-dodecanethiol and
11-mercaptoundecanoic acid. On such surfaces, it is observed that acid and
base wet in a unidirectional manner toward corresponding directions that
are modified by amino or carboxyl groups, which is caused by asynchronous
change of wetting property on two sides of the asymmetric structures. The
as-prepared Janus surfaces could regulate the wetting behavior of acid and
base and could direct unidirectional wetting of water with reversed directions
when the surfaces are treated by strong acid or base. Due to the excellent
response capability, the smart surfaces are potential candidates to be
applied in sensors, microfluidics, oil/water separation, and smart interfacial
design.